1. Technical Field
The present disclosure relates to a bearing structure in which a shaft is supported by a semi-floating metal bearing, and to a turbocharger.
2. Description of the Related Art
Heretofore, there is known a turbocharger in which a shaft is supported rotatably by a bearing housing and the shaft is provided with a turbine wheel at one end of the shaft and a compressor wheel at the other end of the shaft. Such turbocharger is connected to an engine, and the turbine wheel is rotated by exhaust gas discharged from the engine, and the compressor wheel is rotated by the rotation of the turbine wheel via the shaft. In this way, the turbocharger compresses air with the rotation of the compressor wheel and sends the air to the engine.
A turbocharger described in Japanese Patent Application Laid-Open Publication (Translation of PCT Application) No. 2013-541676 (Patent Literature 1) includes a bearing housing, a bearing holder accommodated in a through-hole of the bearing housing, and a semi-floating metal bearing accommodated in the bearing holder. The semi-floating metal bearing is a kind of bearings, and has a through-hole into which a shaft is inserted. On an inner circumferential surface of the through-hole of the semi-floating metal bearing, a bearing surface that receives a radial load of the shaft is formed. Note that, in the case of the semi-floating metal bearing in Patent Literature 1, movement in the axial direction and rotating direction of the shaft is regulated. Further, the bearing holder has a press-fit portion to be press-fitted into the through-hole of the bearing housing, on both end sides of the shaft in the axial direction.